add module meanings existing in NXsensor/measurement

[jkotan]

We works on mapping bettween SECoP and NeXus format.
To make the mapping more direct it would good to add module meanings which exist on the NeXus side as NXsensor/measurement (https://manual.nexusformat.org/classes/base_classes/NXsensor.html#nxsensor) but they are missing in SECoP module 'meaning's.
There are "ph", "conductivity", "resistance", "voltage", "surfacepressure", "stress", "strain", "shear".